Offshore wind farm
Floating offshore wind farms: sounds promising …
In 1989 the first version of the video game SimCity came on the market. SimCity lets the player act as the developer of a patch of green land and found a city. The promise of floating offshore wind farms is in some way similar. Take a piece of windy ocean and develop it to generate electricity. Modern technology allows us to explore the remotest places. We can manage wind farms as a SimCity-like environment. Many specialist contractors are open to the challenge of constructing such an offshore wind farm. Maintenance of such wind farms is feasible and maintenance contractors tell us they are ready — but are they?
Thirty years after the launch of SimCity, this blog guides you through some of the maintenance challenges posed by floating offshore wind farms.
Typically, you would like to plan your floating wind farm far offshore. The environmental and above all the societal impacts seem to decrease in proportion to distance from shore. The chances of being granted a permit are better in remote areas. You will have to accept the disadvantage of long travel and transport times. Another disadvantage is that you cannot use the seabed as a foundation for your wind turbines and jack-up vessels.
If you are able to acquire wind turbines that do not fail during their entire lifetime, your challenges are restricted to the construction phase. However, let’s be realistic. We know that parts of the generator will require maintenance and will occasionally need to be replaced. Fortunately, the industry has developed technologies to overcome these challenges.
Lifting floating to floating
One of the toughest challenges is lifting. Some marine equipment is able to lift to the nacelle; some can lift the generator or the gearbox. However, such equipment is scarce and will fail unpredictably. The costs involved will leave you no option but to wait for other components to fail as well, so that you can bundle the critical lifts into one subcontract scope.
The industry is working hard to come up with hybrid solutions. Conbit is one of the frontrunners, with a concept of temporary lifting equipment installed at the nacelle. This equipment lowers the component for transfer to a construction vessel. The lifting equipment and a suitable construction vessel can arrive at any remote site within a matter of days to execute the replacement procedure.
Accommodation and Access
The walk-to-work market is developing rapidly. The combination of accommodation and access is in high demand, especially in the offshore wind market. The standard walk-to-work vessel accommodates sufficient staff and has favourable characteristics for safe and efficient transfer of people. For remote wind farms, this might not be suitable. Owners of floating wind farms are requesting an EPC approach to their unplanned maintenance activities. The perfect vessel for a replacement job will have: (1) the required lifting capacity; (2) sufficient deck area to accommodate both the old and the new component(s), as well as the installation equipment; and (3) enough beds for the required project crew.
Conbit's "Integrated Projects" Approach
Cost-efficient maintenance of remote floating wind farms requires a turnkey approach, whereby a single party is responsible for realising the complete scope of work. The interaction with the different subcontractors has to be streamlined to ensure that the wind turbine is up and running as soon as possible. The resources identified to complete the scope have to be optimized and used effectively to minimize costs.
Conbit has extensive experience in this kind of project. We are not dependent on our own marine assets, and we can act fast to meet any requirement of our clients. Our in-house engineering enables smooth decision-making at an early stage of the project. The selection of expensive equipment (such as a construction vessel) can be based on the specific project requirements. Conbit’s ‘Integrated Projects’ approach minimises over-allocated resources.